点焊电极用Cu-Ni-Si-Cr-Zr合金性能研究
发布时间：2018-06-17 19:03
本文选题：Cu-Ni-Si-Cr-Zr合金 + 时效处理 ； 参考：《南昌航空大学》2015年硕士论文
【摘要】：电阻点焊是薄板连接的一种重要工艺方法。点焊电极是整个点焊过程中最易损耗的材料之一。随着点焊技术应用于镀锌钢板、高强铝合金连接领域,电极失效问题更为突出,研制长寿命电极材料势在必行。本文在不同成分Cu-Ni-Si合金中添加Cr、Zr、B元素,通过合金化法制备了Cu-2.8Ni-0.7Si-0.6Cr-0.15Zr(WNi/Si=4:1)、Cu-2.8Ni-0.7Si-0.6Cr-0.15Zr-0.06B(WNi/Si=4:1)、Cu-2.8Ni-0.9Si-0.6Cr-0.15Zr(WNi/Si㩳4:1)、Cu-2.8Ni-0.56Si-0.6Cr-0.15Zr(WNi/Si㧐4:1)、Cu-0.6Cr-0.15Zr共5个成分的合金。系统研究了合金成分配比及不同热处理工艺对合金导电性及力学性能的影响。主要研究内容及结论如下:1.Cu-Ni-Si-Cr-Zr合金铸态组织主要由粗大的柱状晶组成,在基体内部弥散分布着大量的粗大过剩相。同时Ni、Si、B元素的引入细化了Cu-0.6Cr-0.15Zr合金铸态组织,使其硬度提升的同时降低了合金导电率。2.对合金进行固溶处理表明:随固溶温度的升高,晶粒长大趋势明显,同时导电率和硬度都快速下降,导电率最低值为16.03%IACS,硬度最低值为94.7HV。3.分析Cu-Ni-Si-Cr-Zr合金时效态成分组成与分布,发现基体中固溶了大量的Ni元素及少量的Si元素。而基体中的析出相颗粒主要富集在晶界处,其成分主要包括CrSi、CuZr、NiSi、B等,颗粒的主要形态有长条形,椭圆形以及圆盘状。4.Cu-Ni-Si-Cr-Zr合金经时效处理后,其导电率和硬度都能都得较大的回升。时效初期,Cu-Ni-Si-Cr-Zr合金导电率快速上升,且温度越高,导电率到达峰值时间越短。随着时效时间延长,导电率上升减缓,最后趋于平稳;对于合金硬度,在450℃和500℃时效时,硬度快速攀升,到后期同样趋于平稳,而在550℃时效初期,合金就已经发生了过时效现象,硬度呈现下降趋势。5.在时效态Cu-Ni-Si-Cr-Zr合金中,合金导电率峰值排序为:%IACS(Ni/Si=4:1)%IACS(Ni/Si=4:1,0.06B)%IACS(Ni/Si4:1)%IACS(Ni/Si4:1);合金硬度峰值排序为:HV(Ni/Si4:1)HV(Ni/Si=4:1,0.06B)HV(Ni/Si=4:1)HV(Ni/Si4:1)。合金成分对导电率的峰值影响有限,在4-9%IACS,而合金成分对硬度峰值的影响,在20-30HV之间。6.本文制备的合金有着良好的抗高温软化性能,合金硬度随温度的上升而下降,当温度上升到550℃-600℃区间时,合金硬度出现大幅下降,各合金软化温度都在550℃以上,其中Cu-2.8Ni-0.7Si-0.6Cr-0.15Zr合金软化温度最高,为601℃。
[Abstract]:Resistance spot welding is an important process for sheet metal joining. Spot welding electrode is one of the most easily worn materials in the whole spot welding process. With the application of spot welding technology in galvanized steel sheet and high strength aluminum alloy connection, the problem of electrode failure becomes more serious, so it is imperative to develop long life electrode material. In this paper, Cu-2.8Ni-0.7Si-0.6Cr-0.15Cr-0.15Zr-WNiR / Si4: 1 alloy Cu-2.8Ni-0.7Si-0.6Cr-0.15Zr-0.06B / Si: 1Cu-2.8Ni-0.9Si-0.6Cr-0.15Zr-0.6Cr-0.15Zr-0.6Cr-0.15Zr-0.56Si-0.6Cr-0.15Cr-0.15Cr-0.15Cr-0.56Si-0.6Cr-0.15Zr alloy with 5 compositions was prepared by alloying method. The effects of alloy composition ratio and different heat treatment processes on the electrical conductivity and mechanical properties of the alloy were systematically studied. The main contents and conclusions are as follows: 1. The as-cast microstructure of Cu-Ni-Si-Cr-Zr alloy is mainly composed of coarse columnar crystals, and a large number of coarse excess phases are dispersed in the matrix. At the same time the microstructure of Cu-0.6Cr-0.15Zr alloy was refined by the introduction of NiOSi-B element, and the hardness of Cu-0.6Cr-0.15Zr alloy was increased and the conductivity of Cu-0.6Cr-0.15Zr alloy was decreased at the same time. The results of solution treatment show that with the increase of solution temperature, the grain length tends to be larger, the conductivity and hardness decrease rapidly, the lowest conductivity is 16.03 IACSs, and the lowest hardness is 94.7HV.3. The composition and distribution of aging state of Cu-Ni-Si-Cr-Zr alloy were analyzed. It was found that a large number of Ni elements and a small amount of Si elements were dissolved in the matrix. The precipitates in the matrix are mainly enriched at grain boundaries, and their compositions include CrSi-CuZr-NiSi-B and so on. The main morphology of the particles is long strip. After aging treatment, the conductivity and hardness of Cu-Ni-Si-Cr-Zr alloy can be increased greatly. The conductivity of Cu-Ni-Si-Cr-Zr alloy increases rapidly in the early aging period, and the higher the temperature, the shorter the time to reach the peak value. With the increase of aging time, the electrical conductivity increases slowly and finally tends to be stable. For alloy hardness, the hardness increases rapidly at 450 鈩，
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